1. Field of the Invention
The present invention relates to methods and apparatus for three dimensional image generation, and in particular for drawing a three dimensional image using a computer.
2. Description of the Related Technology
Image creation using a computer is well established in two dimensions. A typical system provides a screen which displays a two dimensional image and an input surface onto which a user may provide user input using a stylus. In some cases the input surface and the screen may be the same entity, thus the user is able to directly “draw” onto an image displayed on the screen. A commercial example of such a system is the Cintiq® tablet produced by Wacom®. The use of such a system for two dimensional image creation is, intentionally, analogous to using a pencil, brush or other such tool on paper or canvas.
Such two dimensional systems thus provide an instinctive and easy to use system for enabling a user to create an image in two dimensions. However, such ease of use has been difficult to replicate in the creation of three dimensional images. Here, three dimensional images is intended to mean an image which has depth data, meaning that the image can be rotated to see it from other angles. The term “three dimensional image” is not intended to cover a two dimensional image representing a three dimensional object—for example a photograph.
One known method of creating a three dimensional image is to build a three dimensional shape as a series of steps, using a system having access to preconfigured functions. For example, a radially symmetrical shape, representing e.g. a vase or glass, may be created by providing a curve defining an outer surface of the shape, and rotating that curve about an axis. In this example the system has access to a rotation function. Such systems have drawbacks in that a user is not only required to have the ability to visualize an object prior to drawing, but also has to be able to express this visualization as the appropriate functions (i.e. as the rotation). In the theory of multiple intelligences proposed by Howard Gardner, the ability to visualize is called visual-spatial intelligence and the ability to express a shape as the appropriate functions is called logical-mathematical intelligence.
The requirement to use both these so called intelligences makes it harder for users to be effective in creating a three dimensional image. For instance, a user who is able to visualize an image, and has the ability to draw that image in two dimensions, may have good visual-spatial intelligence, but may then struggle to use this ability to effectively create a suitable image in three dimensions due to a difficulty in being able to express the visualized image as the appropriate functions, i.e. because that user has poor logical-mathematical intelligence.
It is an object of the present invention to make the process of creating a three dimensional image easier for a user.